Of the 28 percent of employers who have fired workers for e-mail misuse, they did so because it violated company policy (64 percent), contained inappropriate or offensive language (62 percent), it was used excessively by the employee (26 percent) or breached confidentiality rules (22 percent) according the study's results.

The 30 percent of bosses who fired workers for Internet misuse said they did so because inappropriate or offensive content had been viewed, downloaded or uploaded (84 percent), company policy had been violated (48 percent) or the Internet had been used excessively (34 percent).

However, at least one HR professional thinks this study is outdated, and that bosses are using these policies to passive-aggressively punish employees who are actually underperforming.

Kris Dunn, a human resources director who blogs at hrcapitalist.com argues that if a boss if terminating someone for excessive use of the Internet, they probably haven't done their job from a performance management perspective.

"My strong belief--excessive Internet use isn't a policy issue, it's a performance issue. There's a lot of variability across managers as to the definition of 'excessive'--Manage what's 'appropriate' in Internet use by managing performance," Dunn explains.